During childbirth, the birth mother is sometimes unable to deliver the child without assistance. In some cases, all that is required is for a nurse, midwife, or attending physician to push down on the birth mother's upper abdomen when she bears down during delivery. In other cases, it is necessary for a physician to perform a cesarean section. For those cases in between the two extremes, some sort of intermediate assistance is often required. Such intermediate assistance generally entails the use of some sort of device to aid in the delivery of the child. These devices may likewise be required to assist a physician during particularly difficult cesarean sections.
One example of such a device is forceps. Forceps, however, tend to be bulky and difficult to operate. In addition, the use of forceps, at the very least, is uncomfortable for the mother and infant and risks injury to both.
Alternative devices to forceps are obstetrical vacuum extractors. One example of such device is described in U.S. Pat. No. 5,019,086. The device comprises a cup, which may be placed onto the child's head, and an elongated hollow stem extending from the base or closed back wall of the cup. The elongated hollow stem is used to position the cup onto the infant's head and to introduce a vacuum pressure into the cup. This vacuum within the cup results in suction between the cup and the infant's head which is then used to maneuver and extract the infant from the birth canal by pulling in an appropriate direction on the gripping device coupled to the stem of the vacuum extractor. A similar device is manufactured and sold by Prism Enterprises, Inc. of San Antonio, Tex.
In the '086 patent, a portion of the stem/gripping device substantially adjacent the cup portion is provided with additional flexibility to permit the elongated stem to be folded into a position substantially parallel to the cup portion to facilitate insertion into the birth canal. While this device has been extremely effective and commercially successful, a device which facilitates a pulling force in plane parallel to the open end of the cup may be desirable when utilizing the device in occipitoposterior presentations, i.e., when the infant's head is disposed such that the crown extends toward the mother's tail bone.
Other examples of obstetric vacuum extractors which might more readily facilitate the exertion of a pulling force in a plane substantially parallel to the open end of the cup are disclosed in U.S. Pat. No. 5,803,926 to Neward (U.S. Ser. No. 08/488,492, which is awaiting issuance), U.S. Pat. No. 4,512,347 to Uddenberg, and U.S. Pat. No. 4,620,544 to O'Neil.
The Neward patent discloses a readily manufactured extractor device having a pair of arms with associated handles extending from opposite sidewalls of the cup. During insertion, one of the arms may be folded over the closed back surface of the cup to provide a low profile for insertion. One or both of the handles may then be used to maneuver the cup during delivery. While the relatively rigid arms of the cup may be used to maneuver the cup in a direction substantially parallel to the plane including the open edge of the cup, it may be difficult to exert a sufficient extraction pulling force in this same plane, but in a direction perpendicular to the direction in which the arms extend.
The Uddenberg reference presents a similar obstetric suction device which includes a two-point pulling arrangement in the form of a string, which extends around an arc of one-half of the cup, substantially adjacent the cup opening, the two ends of the string then extend from opposite sidewalls of the cup. The string is coupled to the cup by two loop-shaped attachments having laterally directed legs disposed within the rolled edge of the cup, and guiding loops disposed substantially adjacent the cup opening, just above the rolled edge. The two loop-shaped attachments are disposed at opposite positions on the sidewall. As with, the Neward device, the Uddenberg device can be difficult to exert a sufficient extraction force in every direction within the plane parallel to the closed back surface of the cup. Additionally, the Uddenberg cup can be expensive and time consuming to manufacture in that it requires both a number of separate components and multiple assembly operations.
The O'Neil cup is similarly quite expensive and time consuming to manufacture. The O'Neil cup is stainless steel and is formed with a recess with a peripherally inwardly facing flange around it. A separate circular metal plate is disposed within the recess below the flange, and a separate annular bearing is provided between the circular plate and the inwardly facing flange such that the circular plate is rotatable within the recess. A diametrically-directed arcuate rod is integrally formed with the circular plate. A ring to which a metal traction chain is attached is loosely held on the rod. While the O'Neil cup provides the user with additional degrees of movement in that the ring may slide back and forth on the rod, and the circular plate may rotate within the recess, the cup is very expensive to manufacture. Not only are the materials used in the cup expensive, but it includes multiple precision components which must be carefully assembled. The tolerances between the cup recess and the circular plate, as well as the annular bearing must be closely maintained in order to ensure proper operation of the cup.